why stop() function doesn't work correctly?

[dubaicv]

`conf = (SparkConf()
#.setMaster("local")
.setMaster("spark://master:7077")
.setAppName("My_APP")
.set("spark.executor.cores", '1')
.set("spark.scheduler.mode", "FAIR")
)

sess = SparkSession.builder.config(conf=conf).getOrCreate()
sess.stop()
DataFrame = sess.sql("show tables")
print(DataFrame)
print(sess)`

This is the program output：
DataFrame[database: string, tableName: string, isTemporary: boolean] <pyspark.sql.session.SparkSession object at 0x7fe3b8e709b0>

Why is sparksesion not closed and what can I do to close it? Thank you